Dovetail Joints Redux

Dovetail jigs make quick work of drawer and case joinery,
but many woodworkers don’t realize that the bits included with the jig can do
much more than rout through and half-blind dovetails. These wedge-shaped
cutters let you create several other joints that are attractive and that offer
a mechanical advantage over their square-edged competition.

Here, I’ll introduce three solid joints that are fast and
easy to make using your router table and almost any dovetail bit. To help you
select the best joint for your next project, I’ve provided quick-reference
guides summarizing strength, complexity, and ease of assembly. In the setup and
cutting instructions, I’ve also included some tips for clean, accurate cuts.

Note: I prefer a bit with a 14° cutting angle. A 7° bit will
work, but that angle isn’t steep enough to clearly distinguish it from
square-edged joints.

A dovetail corner rabbet puts a fresh angle on common corner
rabbets. The Z-shaped joint locks the side and end together, but what I like
best about it is that it’s a single-setup joint. When building a run of drawers
and boxes, I’ll set up my router table to join the corners, freeing up my
tablesaw for other operations. (Note: A standard 1⁄2" dovetail bit works
well on stock up to 5⁄8" thick. For 3⁄4" stock you’ll need a larger
bit with more cutting height.)

This joint is a cinch to cut on the router table. First, cut
your end and side stock to length, carefully squaring the parts. Next, chuck a
dovetail bit into the router, and set the height less than the thickness of
your stock (I aim for a 1⁄8" lip). Now rout the end piece flat on the table, using a
backer block to guide the cut and prevent tear-out (Photo A).

Without readjusting the fence or bit, rout the inside face
of the side vertically (Photo B). Again, use a block to steady the stock and
prevent tearout on the trailing edge.

Now for the “tricky” part. Test-fit your front and side. Reposition the fence,
and recut the two test pieces until the outer lip of the front piece is flush with the outer face of
the side. (I set the fence so that the lip runs a bit long and plane it flush after assembly.)

Like a square-edged rabbetted corner, this joint requires
clamps during assembly, but I find
the angled edges simplify alignment and require fewer clamps for tight joints.

The half-dovetail prevents the ends from pulling away from
the sides, but the sides offer no resistance against the ends pulling away, so
additional reinforcement is necessary. After the glue-up cures, pin the sides
to the ends with dowels (Photo C).

Dovetail keys reinforce notoriously weak miter joints much
like straight splines, but with flair.
These decorative “mock dovetails” are suitable for jewelry boxes and other
projects where all sides will be visible. You can use this joint on drawers or
boxes, with the key size dictated by the height of your bit.

Compared to traditional through-dovetail construction, this
joint is simple to cut. However, it requires a bit more preparation than the
dovetail rabbet. Before making and installing the keys, you’ll need to miter,
glue, and assemble the box. You’ll also need to build a simple sled like the
one shown in Photo D.

To rout the slots, install a dovetail bit into your table-mounted
router, and adjust the height of the bit so it will be just shy of the box
interior with the box riding diagonally on the jig. Clamp stopblocks to the jig
to prevent the box from shifting; then rout the sockets, pushing the sled over
the bit as shown (Photo D).

Once the sockets are cut, make the dovetail keys. First,
prepare a length of key stock wider than the widest part of the socket. Raise
the same router bit to full height and rout the sides against a fence, as shown
in Photo E. (For snug fitting
key stock, take your time and creep up on your cut.)

After you’ve milled the key stock to fit, cut the strip into individual blocks that
sit proud of their respective slots. Apply glue, tap the keys into their slots,
and wipe off any squeeze-out. Once the glue has dried, trim the keys close to
the sides of the box, and then sand or plane them flush to your work, as shown in Photo F.

The sliding dovetail’s selling point is strength. Unlike the
previous joints, it does not need pins, keys, or (when done well) glue; the
dovetail on one piece slides into a socket in the other. This joint can be used
without glue (on breadboard ends, for example) when you want to allow for wood
movement. This attribute translates to easy assembly without needing clamps.

The joint isn’t difficult
to make, but the fit
must be precise. Too loose, and it won’t work; too tight, and it may seize up
as you try to slide the pieces together. Longer joints require a slightly
looser fit, otherwise
they might get stuck midway. I reserve it for relatively narrow work and make
sure my stock is accurately jointed and planed.

Rout the socket first.
To do this, mark the centerline of the cut. Then outfit your router with a straight bit thinner than
the thinnest section of your dovetail bit, and hog out the bulk of the waste (Photo
G). Without changing the position of the fence, install a dovetail bit, set the
bit to full depth, and rout the socket (Photo H).

Without changing the height of the bit, attach the fence and
rout the tails on the ends of your sides (Photo I). As with the dovetail keys,
partially recess the bit into the fence, and rout both faces of your side
stock. Test-fit the
resulting dovetail in one of the sockets. The joint should go together with firm hand pressure or a light
tap from a mallet.

The trickiest part of making a sliding dovetail drawer is
cutting the back to length. After routing the front ends of the sides, rout
sockets in the sides and assemble your “backless” drawer. Transfer the
socket-to-socket length as shown (Photo J). Cut the back to fit, rout dovetails on both
ends. and assemble your finished
drawer.